The Multi Particle Simulation for the Cyclotron NIRS-930

The simulation of the beam for the cyclotron NIRS-930 at NIRS has been performed with the use of the SNOP program* in order to study beam dynamics in a cyclotron and to improve beam intensity. SNOP simulated from beam injection to extraction with the electric fields of the inflector, the Dee electrodes and the deflector; the magnetic fields of the main coils, the trim coils and the harmonic coils and the magnetic channel which were calculated by OPERA-3d. The simulation of proton with 30 MeV extraction energy with harmonic number of 1 was already performed and well simulated RF phase and extraction efficiency**. Then we tried to apply SNOP to 18 MeV protons with harmonic 2. We first formed isochronous magnetic field with main and trim coils for simulating single particle. Next we optimized electric deflector and magnetic channel in order to maximize extraction efficiency simulating the bunch of particles. Beam loss of the simulation was compared to the experiment. We intend to apply optimized simulation parameters for actual cyclotron operation to improve beam intensity and quality